• 165,644 lbs Max Gross Vehicle Weight
  • 473 @2000 rpm Gross HP
  • 44.1 U.S. tons Capacity


The 44.1 ton capacity HM400-5 is powered by a Tier 4 final Komatsu engine. A Komatsu Traction Control System along with two working modes and a standard payload meter (PLM) provide the operator with the tools needed to complete the job efficiently and profitably even in the most severe underfoot conditions. A heated, center located air suspension operator seat, a forward facing training seat, separate rear view monitor, and large LED multi-language monitor ensure the operator is working productively in comfort throughout a full shift.

HM400-5 Walkaround  >


Tier 4 Final Engine

The Komatsu SAA6D140E-7 engine is EPA Tier 4 Final emissions certified and provides exceptional performance while reducing fuel consumption. Based on Komatsu proprietary technologies developed over many years, this new diesel engine reduces nitrogen oxides (NOx) by more than 80% when compared to Tier 4 interim levels. Through the in-house development and production of engines, electronics, and hydraulic components, Komatsu has achieved great advancements in technology, providing high levels of performance and efficiency in virtually all applications.

Komatsu Auto Idle Shutdown

Komatsu auto idle shutdown automatically shuts the engine down after idling for a set period of time to reduce unnecessary fuel consumption and exhaust emissions. The amount of time before the engine is shutdown can be easily programmed from 5 to 60 minutes.

Selectable Working Modes

Power mode
Appropriate for higher production jobs and uphill hauling applications. The power mode increases the engine maximum output and raises the upshift and downshift engine speeds during operation.

Economy mode
Appropriate for lighter work on flat ground. The economy mode lowers the engine maximum output along with lowering the upshift and downshift engine speeds during operation.

Large Capacity Body

The HM400-5 has a heaped body capacity of 24.0 m3 / 31.4 yd3. The low loading height of 3164 mm 10'4" enables easy loading. The body is built of high strength, wear-resistant steel with a Brinell hardness of 400 and the body shape provides excellent load stability. HM400’s frame employs a rigid box structure utilizing high tensile strength steel - rugged enough for the toughest jobs.

Komatsu Designed Electronically Controlled Countershaft Transmission

The Komatsu designed electronically controlled transmission called K-ATOMiCS has been a success in Komatsu’s dump trucks. The electronic clutch modulation system ensures proper clutch pressure when the clutch is engaged. The total control system controls both the engine and the transmission by monitoring the vehicle conditions. This high technology system assures smooth shifts with minimal shock and maximizes the power train life.

Komatsu Traction Control System (KTCS)

The KTCS was developed by Komatsu to allow for maximum machine performance in soft and slippery ground conditions. Komatsu leveraged its prior experience with the traction control systems in bulldozers and rigid dump trucks to develop this system for use in articulated dump trucks.

The KTCS monitors the wheel speeds on the front and middle axles. If the system detects wheel slip, it will automatically engage the inter axle lock to improve machine performance. If the machine continues to detect wheel slip it will brake the wheel that slip was detected on. It will continually monitor the wheel speeds and engage the brakes as necessary.

KTCS is automatically activated and deactivated. The inter-axle lock can also be engaged by the operator via a rocker switch located on the dash panel.

Payload Meter (PLM)

A payload meter is included as standard equipment on the new HM400-5. The payload tonnage is displayed on the Machine Monitor and is visible to the haul truck operator. An external display lamp mounted on the top of the cab communicates payload status to the loader operator. The external display lamp indicator lights are visible from both sides of the truck so it is always in sight of the loader operator.

PLM data is transmitted by KOMTRAX and can be accessed via the internet. Detailed data is stored in the truck’s controller and can be directly downloaded from the truck to a PC.

Rear View Monitoring System

The rear view camera and monitor are equipped as standard.

Hydraulically Controlled Wet Multiple-disc Brakes and Retarder

Wet multiple-disc brakes with proven performance in other Komatsu dump trucks are tailored for use in the HM300-5. The large-capacity, continuously cooled, wet-multiple disc brakes also function as a highly responsive retarder which gives the operator greater confidence at higher speeds when travelling downhill.

Retarder Absorbing Capacity (continuous descent): 510 kW 684 HP

ECO Guidance

The monitor panel provides guidance to the operator to help promote energy saving operation. For example, if the operator stops the machine for a long period of time with the engine idling, the message “Avoid excessive engine idling” is displayed on the monitor panel. The ECO guidance function displays six (6) messages:

  • Avoid Excessive Engine Idling
  • Release the Hoist Lever
  • Operating the Accelerator Pedal with Brake Actuated Lowers Fuel Economy
  • Shift Up
  • Avoid Operating the Accelerator Pedal with the Body Moving Down
  • Avoid Hard Use of Steering

ECO Gauge

The ECO gauge indicates a momentary fuel consumption rate during operation.

Operating the machine by keeping the gauge within the green zone leads to energy-saving operation.

Ground Access to Filters

The oil filters of the transmission and the brake systems can be serviced from ground level.

Easy Access DEF Tank

Located to the rear of the fuel tank, and easy to access.

Tiltable Cab with Power Tilt

The cab can be tilted rearward by 29 degrees to provide easy access to the engine and transmission for service. Electrically-operated cab tilt is standard.



Komatsu SAA6D140E-7*
Water-cooled, 4-cycle
Komatsu variable geometry, turbo-charged, after-cooled, cooled EGR
Number of cylinders
Bore 140 mm 5.51"
Stroke 165 mm 6.5"
Piston displacement 15.24 ltr 928 in3

SAE J1995 353 kW 473 HP
ISO 9249 / SAE J1349 348 kW 466 HP
Rated rpm
2000 rpm
Fan drive type
Maximum torque 2263 Nユm
231 kgユm
1669 ft lbs
Fuel system
Direct injection
Electronically controlled
Lubrication system:

Gear pump, force-lubrication
Full-flow type
Air cleaner
Dry type with double elements and precleaner (cyclonpack type), plus dust indicator
*EPA Tier 4 Final emissions certified


Torque converter
3-elements, 1-stage, 2-phase
Full-automatic, counter-shaft type
Speed range
6 speeds forward and 2 reverse
Lockup clutch
Wet, single-disc clutch
Torque converter drive in 1st gear, direct drive in 1st lockup and all higher gears
Torque converter drive and direct drive in all gear
Shift control
Electronic shift control with automatic clutch modulation in all gear
Maximum travel speed 55.9 km/h 34.7 mph


Full time all wheel drive

Final drive type Planetary gear
Differential 3.727
Planetary 4.941

Suspension System

Front Hydro-pneumatic suspension
Rear Combined hydro-pneumatic and rubber suspension system

Steering System

Articulated type, fully hydraulic power steering with two double-acting cylinders
Supplementary steering
Automatically actuated, electrically powered
ISO5010, SAE J1511
Minimum turning radius, wall to wall 8.8 m 28' 10"
Articulation angle
45° each direction


Standard ISO3449 (FOPS)
ISO3471 (ROPS)


Service brakes Full-hydraulic control, oil-cooled multiple-disc type on front and center axles
Standard ISO3450
Parking brake Spring applied, caliper disc type
Retarder Front and center axle brakes act as retarder

Main Frame

Type Articulated type, box-sectioned construction on front and rear Connected by strong torque tubes.


Struck 18.2 m3 23.8 yd3
Heaped (2:1, SAE) 24 m3 31.4 yd3
Payload 40 metric tons 44.1 U.S. tons
Material - high tensile strength steel 130 kg/mm2 184,925 psi
Material thickness:
Bottom 16 mm 0.63"
Front 8 mm 0.31"
Sides 12 mm 0.47"
Target area - (inside length x width) 5667 mm x 3194 mm 18' 7" x 10' 6"
Heating Exhaust heating (option)

Hydraulic System

Hoist cylinder Twin, telescopic type
Relief pressure 28.4 Mpa / 290 kg/cm2   4119 psi
Hoist time 12.0 sec

Weight (approximate)

Empty weight 35005 kg 77,283 lbs
Gross vehicle weight 75135 kg 165,644 lbs
Weight distribution:
Empty: Front axle 56.9%
Center axle 23.6%
Rear axles 19.5%
Loaded: Front axle 30.4%
Center axle 35.8%
Rear axles 33.8%


Standard tire 29.5 R25

Service Refill Capacities

Fuel tank 525 L 138.7 U.S. gal
DEF tank 34.0 L 9.0 U.S. gal
Engine oil 50 ltr 13.2 U.S. gal
Torque converter, transmission and retarder cooling 125 L 33 U.S. gal
Differentials (total) 108 L 28.5 U.S. gal
Final drives (total) 32 L 8.5 U.S. gal
Hydraulic system 167 L 44.1 U.S. gal
Suspension (total) 21.4 L 5.7 U.S. gal



  • Air cleaner: dry type with double elements and pre-cleaner, plus dust indicator
  • Alternator, 24 V / 90 A
  • Batteries, 2 x 12 V / 160 Ah, 910 CCA
  • Engine, Komatsu SAA6D140E-7 (with EGR)
  • Hydraulically driven reversible cooling fan, after cooler
  • Hydraulically driven reversible cooling fan, radiator
  • Komatsu Diesel Particulate Filter (KDPF)
  • Komatsu Variable Displacement Turbocharger
  • Selective Catalytic Reduction (SCR)
  • Starting motor, 11.0 kW
  • Two mode power system (Power and Economy)


  • 2 x DC12V electrical outlets
  • Air conditioner
  • AM/FM radio with AUX terminal
  • Ashtray
  • Cigarette lighter
  • Color rear view monitor
  • Cup holder
  • Front wiper (with washer and intermittent)
  • Machine monitor (color LCD)
  • Operator seat, heated , reclining, air suspension type with 3-point retractable seat belt
  • Passenger seat with 2-point retractable seat belt
  • Power window (L.H)
  • Rear wiper (with washer)
  • Space for lunch box
  • Steering wheel, tilt and telescopic
  • Sun visor, front window
  • Tiltable ROPS cab with FOPS, sound suppression type


  • Back-up lamp
  • Back work lamps, LH and RH side
  • Front, cab mounted work lamps
  • Hazard lamps
  • Head lamps (High/Low)
  • LED stop, tail and turn signal lamps


  • Engine underguard
  • Exhaust muffler thermal guard
  • Fire prevention covers
  • Propeller shaft guards, front and rear
  • Transmission underguard


  • Electronic hoist control system


  • 29.5 R25


  • Alarm, backup
  • Anti-slip material on fenders
  • Auto idle stop function
  • Back-up alarm
  • Battery disconnect switch
  • Centralized greasing
  • Coolant temperature alarm and lamp
  • Dump counter
  • Ecology guidance and ecology gauge
  • Electric circuit breakers, 24 V
  • Electric priming fuel pump
  • Engine shutdown secondary switch
  • Full-automatic F6-R2 transmission with lock-up torque converter & K-ATOMiC shift control
  • Guard rails
  • Horn, electric
  • Hydropneumatic suspension, front and rear
  • Komatsu Traction Control System (KTCS)
  • KOMTRAX Level 5
  • Mud guards
  • Parking brake
  • Payload Meter (PLM)
  • Power cab tilt
  • Protective grille for rear window
  • Provision for tailgate installation
  • Heated rear view mirrors
  • Rear view monitoring system
  • Retarder/brake system
  • Secondary brake
  • Secondary engine shutdown switch
  • Secondary steering, automatic, electric
  • Side markers
  • Steering joint locking assembly
  • Step (right side) and ladder (left side)
  • Tool box
  • Under view mirrors


  • Body, 24.0 m3 31.4 yd3, SAE 2:1 heaped, unlined floor
  • Body, with exhaust heating ducting, 24.0 m3 31.4 yd3, SAE 2:1 heaped, unlined floor
  • Spare rim, for 29.5 x 25 tire (1 rim only)
  • Tail gate, scissor type